We evaluated patterns of species richness, heterogeneity, niche occupation, and community structuring/similarity of staphylinid beetles of the subfamily Steninae across a 2500-m elevational gradient of a tropical mountain area in Northern Thailand. Predaceous Steninae were collected from a variety of habitat types. Increasing Sørensen dissimilarity with increasing elevation was explained by both species turnover (especially across the lower elevational zones) and declining numbers of species (especially across elevations > 1400 m). Unlike the strong decline of the number of species with increasing elevation, species density (i.e., total number of species divided by the number of collection sites at the respective elevational zone) showed a much smoother decline suggesting that the negative gradient in the number of species was superimposed by a land-area effect inherent in mountain shape. In both the litter-inhabiting species and waterfall-associated species, the numbers of species showed a mid-elevational peak. Species frequency was positively correlated to both elevational (“ Dianous ” and Stenus ) and habitat niche width ( Stenus only). Stenus showed high interspecific variety of wide to narrow niche widths for both elevation and habitat. Numbers of Palearctic and Oriental species deviated from statistical expectation, suggesting that climate niche conservatism has played a role in their elevational distribution. The distributional patterns of “ Dianous ” beetles, with their strong hygrobiont preferences associated with rocks in running water and waterfalls, are potentially explained by source–sink dynamics along mountain streams.

中文翻译：

---

泰国北部山坡上热带甲虫（鞘翅目：葡萄科：蝽科）的物种丰富度、群落结构和生态位占据的海拔梯度

我们在泰国北部热带山区 2500 米的海拔梯度上评估了 Steninae 亚科葡萄甲虫的物种丰富度、异质性、生态位占据和群落结构/相似性的模式。从各种栖息地类型收集捕食性 Steninae。随着海拔的增加，Sørensen 差异的增加可以通过物种周转（尤其是在低海拔地区）和物种数量减少（尤其是海拔 > 1400 m）来解释。与物种数量随海拔升高而急剧下降不同，物种密度（即 物种总数除以各自海拔区域的收集点数量）显示出更平稳的下降，这表明物种数量的负梯度是由山地形状固有的土地面积效应叠加的。在凋落物栖息物种和瀑布相关物种中，物种数量均显示出中海拔峰值。物种频率与海拔（“Dianous”和 Stenus）和栖息地生态位宽度（仅 Stenus）呈正相关。Stenus 在海拔和栖息地都显示出从宽到窄的生态位宽度的高种间变化。古北和东方物种的数量偏离了统计预期，表明气候生态位保守性在其海拔分布中发挥了作用。“Dianous”甲虫的分布格局，